It's impossible to point to any single reason that Friends became the pop-culture phenomenon that it undeniably remains today. The cast is perfect, but so too is the writing, each working in stellar concert with the other.
But much as it feels like Friends' pin-sharp comedy was engineered and workshopped down to the very finest variable, the show actually contains far more off-the-cuff, unscripted, and improvised moments than you'd probably ever expect.
The high-pressure nature of a live studio audience taping might not seem the most conducive to on-the-fly creativity, and yet, many of the show's most memorable gags and unforgettable one-liners absolutely came at the spur of the moment.
These 10 unscripted moments all came to pass because the actors involved - most commonly Matthew Perry, unsurprisingly - had the good sense to go with their gut and experiment around.
Though writers can get awfully precious about their scripts, clearly Friends' set was a highly collaborative one, where the cast were given the necessary freedom to figure out what worked best.
And going by these incredible unplanned moments, their instincts were totally on the money...
10. "You Have To Stop The Q-Tip When There's Resistance"
Matthew Perry is responsible for a large number of Friends' improvised one-liners, but there's no better (or funnier) example of his quick wit than this pithy clapback in the season two premiere, "The One with Ross's New Girlfriend."
When Joey (Matt LeBlanc) fails to carry out some basic maths related to his age, a frustrated Chandler (Perry) admonishes him, "You have to stop the Q-tip when there's resistance."
It's an hilarious and unforgettable line, and yet one that incredibly wasn't in the script at all. Chandler was supposed to simply sneer at Joey and walk off, but Perry ad-libbed the line on the spot and dug up prime comic gold in the process.
Perry also declared in a recent interview that it's his favourite one-liner of the entire show, and considering the euphoric reaction it received, his pride is most certainly well-earned.